Image Projection Apparatus, and System Employing Interactive Input-Output Capability

1. An image projection system, comprising: an image projection apparatus to receive input image data from an external apparatus; and a coordinate input device communicably connected to the image projection apparatus, wherein the coordinate input device includes first processing circuitry to acquire measurement information from a projection screen pointed to by the coordinate input device, wherein the image projection apparatus includes second processing circuitry configured to calculate coordinates of a point on the projection screen pointed to by one end of the coordinate input device, based on the measurement information obtained from the coordinate input device; calculate a distance between the coordinate input device and the coordinates of the point on the projection screen; and determine whether a movement of the coordinates of the point on the projection screen pointed to by the coordinate input device is to be reproduced on the projection screen, depending on the calculated distance between the coordinate input device and the coordinates of the point on the projection screen.

2. The image projection system of claim 1 , wherein the first processing circuitry measures the coordinates of the point based on pattern information embedded on the projection screen pointed to by the coordinate input device.

3. The image projection system of claim 1 , wherein the first processing circuitry is further configured to: calculate a moved length of the coordinate input device, and calculate a swing angle of the coordinate input device; and the second processing circuitry is further configured to calculate a moved length of the coordinates of the point on the projection screen from the measurement information, and calculate the distance between the coordinate input device and the coordinates of the point on the projection screen based on (i) the calculated swing angle of the coordinate input device, (ii) the calculated moved length of the coordinates of the point on the projection screen, and (iii) the calculated moved length of the coordinate input device.

4. The image projection system of claim 3 , wherein the second processing circuitry is further configured to correct the moved length of the coordinates of the point on the projection screen based on the calculated moved length of the coordinate input device to generate a corrected moved length of the coordinates of the point on the projection screen, and calculate the distance between the coordinate input device and the coordinates of the point on the projection screen based on the corrected moved length of the coordinates of the point on the projection screen and the calculated swing angle of the coordinate input device.

5. The image projection system of claim 4 , wherein the second processing circuitry is further configured to correct the moved length of the coordinates of the point on the projection screen based on the calculated moved length of the coordinate input device to generate a corrected moved length of the coordinates of the point on the projection screen, only when the calculated moved length of the coordinate input device is greater than zero.

6. The image projection system of claim 3 , wherein the second processing circuitry is further configured to convert the calculated coordinates of the point to operation information used for an operation of the external apparatus; and transmit the operational information to the external apparatus, when the calculated moved length of the coordinates of the point on the projection screen exceeds a predetermined threshold.

7. The image projection system of claim 1 , wherein the image projection apparatus includes a projector to project a projection image onto the projection screen; and the image projection system further comprises the external apparatus, which is configured to output an image signal used to generate the projection image projected by the projector.

8. An image projection apparatus, comprising: a projector to project a projection image onto a projection screen based on received image data; and processing circuitry configured to receive the input image data from an external apparatus; calculate coordinates of a point on the projection screen pointed to by one end of a coordinate input device, based on the measurement information obtained from the coordinate input device, the coordinate input device being communicably connected to the image projection apparatus; calculate a distance between the coordinate input device and the coordinates of the point on the projection screen; and determine whether a movement of the coordinates of the point on the projection screen pointed to by the coordinate input device is to be reproduced on the projection screen, depending on the calculated distance between the coordinate input device and the coordinates of the point on the projection screen.

9. A method, comprising: receive input image data from an external apparatus; project a projection image onto a projection screen based on the input image data; calculate coordinates of a point on the projection screen pointed to by one end of a coordinate input device, based on the measurement information obtained from the coordinate input device, the coordinate input device being communicably connected to the image projection apparatus; calculate a distance between the coordinate input device and the coordinates of the point on the projection screen; and determine whether a movement of the coordinates of the point on the projection screen pointed to by the coordinate input device is to be reproduced on the projection screen, depending on the calculated distance between the coordinate input device and the coordinates of the point on the projection screen.

10. The method of claim 9 , wherein the step of calculating the distance comprises: calculating a moved length of the coordinates of the point on the projection screen from the measurement information, and calculating the distance between the coordinate input device and the coordinates of the point on the projection screen based on (i) a calculated swing angle of the coordinate input device, (ii) the calculated moved length of the coordinates of the point on the projection screen, and (iii) a calculated moved length of the coordinate input device.

11. The method of claim 10 , wherein the step of calculating the distance further comprises: correcting the moved length of the coordinates of the point on the projection screen based on the calculated moved length of the coordinate input device to generate a corrected moved length of the coordinates of the point on the projection screen, and calculating the distance between the coordinate input device and the coordinates of the point on the projection screen based on the corrected moved length of the coordinates of the point on the projection screen and the calculated swing angle of the coordinate input device.

12. The method of claim 9 , further comprising: converting the calculated coordinates of the point to operation information used for an operation of the external apparatus; and transmitting the operational information to the external apparatus, when the calculated moved length of the coordinates of the point on the projection screen exceeds a predetermined threshold.